<?php
/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2018/4/5
 * Time: 13:58
 */

namespace app\api\service;


use app\api\model\User as UserModel;
use app\lib\enum\ScopeEnum;
use app\lib\exception\TokenException;
use app\lib\exception\WxchatException;
use think\Exception;

class UserToken extends Token
{
    protected $code;
    protected $wxAppID;
    protected $wxAppSecret;
    protected $wxLoginUrl;

    function __construct($code)
    {
        $this->code = $code;
        $this->wxAppID = config('wx.app_id');
        $this->wxAppSecret = config('wx.app_secret');
        $this->wxLoginUrl = sprintf(config('wx.login_url'),
            $this->wxAppID,$this->wxAppSecret,$this->code);
    }

    public function get()
    {
        $result = curl_get($this->wxLoginUrl);
        $wxResult = json_decode($result, true);
        if (empty($wxResult)){
            throw new Exception('获取openId失败，微信内部异常');
        }
        else{
            $loginFail = array_key_exists('errcode',$wxResult);
            if ($loginFail){
                $this->processLoginError($wxResult);
            }else{
                return $this->grantToken($wxResult);
            }
        }
    }

    private function grantToken($wxResult){
        //拿到openid
        //数据库比对openid
        //如果不存在新增到user
        //生成令牌准备缓存数据，写入缓存
        //把令牌返回到客户端
        //key: 令牌
        //value: wxResult, uid, scope
        $openid = $wxResult['openid'];
        $user = UserModel::getByOpenid($openid);
        if ($user)
        {
            $uid = $user->id;
        }
        else{
            $uid = $this->newUser($openid);
        }
        $cachedValue = $this->prepareCachedValue($wxResult, $uid);
        $token = $this->saveToCache($cachedValue);
        return $token;
    }

    private function saveToCache($cachedValue)
    {
        $key = self::generateToken();
        $value = json_encode($cachedValue);
        $expire_in = config('setting.token_expire_in');
        $request = cache($key, $value, $expire_in);
        if (!$request){
            throw new TokenException([
                'msg' => '服务器缓存异常',
                'errorCode' => '10005'
            ]);
        }
        return $key;
    }
    private function prepareCachedValue($wxResult, $uid)
    {
        $cachedValue = $wxResult;
        $cachedValue['uid'] = $uid;
        $cachedValue['scope'] = ScopeEnum::User;
        //$cachedValue['scope'] = 15;
        return $cachedValue;

    }
    private function newUser($openid)
    {
        $user = UserModel::create([
            'openid' => $openid
        ]);
        return $user->id;
    }

    private function processLoginError($wxResult)
    {
        throw new WxchatException([
            'msg' => $wxResult['errmsg'],
            'errorCode' => $wxResult['errcode']
        ]);
    }

}